The present invention relates to a method for restressing and locking HHL anchor, in which it can provide a more simple device for stressing, restressing and adjusting the anchor.
In order to maintain the strength of land in civil engineering work, an effective method is to pile land anchor into the land at an appropriate location. In prior art, the traditional anchor transfers the load downward from top of the fixed end. Since the hardened cement grout is much weaker in tension than in compression, the top-to-bottom load transferring mechanism tends to create cracks along the bond length of anchor and consequently may result in strand corrosion in the long run. And in the place where the geological stratums are stanstone, mudstone, schist, shale, meathering rock, fractured rock, gravel, sand slit, caly, etc., the prestress of the anchor are often increased or reduced to a dangerous range because of heavy rain and/or earthquake moving the surrounding earth. However, no appropriate method is available to restress the strength of anchor after the piling work and the defects in engineering work will still cause a great damage to the land structure
I, the inventor, have invented a method and testing device for HHL land anchorage applied for U.S. patent on Jan. 7, 1988 with application Ser. No. 141,377, now abandoned. The said invention comprises a pulling force adjusting nut mounted onto an anchor head portion for testing its pulling force, a rigid central rod for connecting to the center of anchor, a supporting base, a jack and a load measuring means orderly mounted to the outer of the rigid rod. By means of the controlling of the jack, which drives the rigid rod to produce a upward pulling force, the pulling force of the land anchor can be determined. Although it can obtain the objective of restressing and testing, it is still not convenient in operation.